Field of the Invention
The present invention relates to a method for dispersing mineral particles by using polyamino acids as dispersing agents. This includes mineral dispersions in aqueous media, detergent compositions for dispersion of soil particles, dispersion of pigments in cosmetics and paints, and dispersion of minerals in making paper.
Discussion of the Background
Dispersions of particles in aqueous and other media are important in many applications; e.g., paints, detergents, cosmetics, and paper. In addition, methods for dispersing mineral particles in aqueous media are important for the prevention of corrosion and scaling of cooling and boiler equipment. Particular problems may arise when the aqueous sample contains more than one kind of mineral particle.
The importance of keeping minerals dispersed in aqueous media has led to much work in this area, and the use of polymers as dispersing agents has been explored. Thus, Bendiksen and Parsons, Proceedings of ACS Division of Polymeric Materials, Vol. 57, pp. 719-725, (1987) disclose the use of sulfonic acid/acrylic acid copolymers and poly(acrylic acid) as dispersing agents for clay and iron oxide. Masler et al., Corrosion 88, paper no. 11, NACE (1988) disclose the use of various acrylic acid copolymers and sulfonated styrene copolymers as dispersing agents for calcium phosphonate. Smyk et al., Corrosion 88, paper no. 14, NACE (1988) disclose the use of various terpolymers which contain monomers derived from acrylic acid as dispersing agents for a variety of minerals. Hoots et al., Corrosion 89, paper no. 175, NACE (1989) discuss the mechanisms by which conventional dispersing agents disperse minerals in aqueous media. U.S. Pat. No. 3,839,215 discloses the use of poly-.alpha.-hydroxyacrylic acid in detergents to sequester metal ions.
The use of polymers based on amino acids as dispersing agents has also been studied. U.S. Pat. No. 4,640,943 discloses the use of polyaspartic acid and polyglutamic acid as surface modifiers for improving the wettability and enhancing the dispersibility of inorganic fillers. German Patent Application DE 37 24 460 discloses the use of polyglutamic acid and polyaspartic acid and their salts as components in wetting compositions which are useful in cleansing and detergent compositions.
U.S. Pat. Nos. 4,428,749 and 4,732,693 disclose the use of polyaspartic acid as an antiredeposition agent in detergent compositions.
Japanese Patent Application Kokai 59-209635 discloses the use of wetting agents which contain polyglutamic acid in shampoos and rinses in hair or skin lotions and in solid or liquid detergents.
U.S. Pat. No. 3,846,380 discloses the use of terminal group derivatized polyaspartic acid and derivatives of polyaspartic acid which may be enriched in polyaspartic acid for use as foaming agents, solubilizing agents, dispersing agents, emulsifying agents, rust-proofing agents, fiber-treating agents, level dying agents, and retarding agents.
Chemical Abstract Vol. 79, 55246 broadly discloses the use of poly(amino acids) as surfactants in detergents in cosmetics. In particular, the use of polyaspartic acid and polyaspartic acid derivatives as surfactants is disclosed.
German Patent Application DE 36 26 672 discloses the use of polyaspartic acid amide and its salt derivatives as a scale remover.
U.S. Pat. No. 4,363,797 discloses the use of polyaspartic acid derivatives which may contain free polyaspartic acid units as a component in shampoos and rinsing lotions.
Japanese Patent Application Kokai 50-38520 discloses photographic compositions which contain polyglutamic acid derivatives and pigment powders.
Japanese Patent Application Kokai 63-28890 discloses the use of polyamino carboxylic acids for the removal of carbonate scale from a geothermal power generation plant.